Door panel

ABSTRACT

A panel formed as a laminate with a decorative fabric at the exposed face includes a pair of foamed resin layers as backing material. Between the foamed resin layers is a fiber glass layer for strength. Means are provided to attach the panel to a substrate.

FIELD OF THE INVENTION

This invention relates to decorative panels formed from polyurethanefoam, fiber glass and a decorative layer at the exposed face. At leastone use is a panel for mounting on the inside surface of an automobiledoor.

BACKGROUND OF THE INVENTION

Current construction of automobile doors includes a plastic shell withvarious openings for door lock connections, electric window controlbuttons, ash trays, door handles and the like. To enhance the decorativeappearance of the inside of doors which incorporate the plastic shell adecorative, fabric covered panel is adhered to the inside of the door.The current way to attach the decorative panel to the door is by way of"toy tabs" which are well known in the industry. Toy tabs are tabs orprongs struck from a metal sheet, the tabs are to project through holesin a substrate and be deformed to one side to lock the metal sheet tothe substrate.

The way the toy tab structure is affixed to the decorative panel is by abonding of the metallic layer at the unexposed face of the panel withthe rearwardly projecting tabs pre-cut for later manipulation.

The decorative panels themselves are a sandwich of various materialsincluding the aforementioned decorative layer on the front and themetallic layer bonded to the back.

Smith U.S. Pat. No. 3,234,064 and Scholl U.S. Pat. Nos. 3,520,755 and3,655,477 et al show the manufacture of a composite piece of foamedmaterials and non-foamed covers to form a panel.

Polk U.S. Pat. No. 3,466,214 et al illustrates a way of forming a panelfrom composite material in a mold with the edge or ridge around the moldincluding a sharp cutting edge which cuts the product to the desiredshape, note particularly FIG. 4. Similar structure in slightly modifiedform is illustrated in Hoyer U.S. Pat. No. 3,075,862.

Braun U.S. Pat. No. 3,355,345 illustrates a mold in FIG. 6 which shows aplurality of product molds on one sheet to be used in a press.

Hammond U.S. Pat. No. 4,350,734 illustrates a composite structureforming a rigid panel which uses one or more layers of open celledpolyurethane foam in forming the panel.

It is noted that none of these cited patents includes a metal sheet asthe back layer of the laminated panel.

The conventional door panel using the metal backing layer has manydefects from a manufacturing and efficiency standpoint. One problem isthat once the metallic backing layer becomes deformed it never quitefits or looks quite right when reshaped to a planar surface. Therefore,in the manufacturing and shipping of the panels it is critical that theybe shipped so that a bend is not applied to the panel.

Another defect is the tab connection between the plastic door shell andthe decorative panel. In order to be properly manipulable by theworkman, the tabs projecting from the metal layer must not be too stiff.Conversely, in order that the door panel not work loose as a result ofhundreds of door openings and closings, the tabs cannot be too flexible.A balance must be struck but it is inherent that the balance will notalways work under all circumstances.

What is needed is a panel of sufficient rigidity as to serve the purposeof the door panel, which will not have a crease problem upon bending andwhich will not be subject to thermal expansion and contraction problemsnor flexing problems from door openings and closings which could resultin the separation of the panel from the plastic door shell.

While the above discussion has been directed specifically to automobiledoor panels, it will be quite obvious that the panels describedpreviously and subsequently are not at all limited to automobile doors.

SUMMARY OF THE INVENTION

To solve the problem in the industry relating to the metallic layer andthe toy tab structure, this invention includes alternative attachingmeans. One such attaching means is a double sided adhesive tape mountedin place of the metallic layer of conventional panels. Anotheralternative way of mounting the panel is by substituting a CHRISTMASTREE structure in the form of a plastic stud having a head on one endand radially extending flanges along its shaft. The stud or studs to bemounted in the panel will project radially from the backside and aredesigned to project through an aperture in the substrate, which aperturewill be smaller in cross-sectional area than that of the flanges on theshaft of the stud. Thereby, when the stud is pushed through the hole,the flanges will deflect and spring back on the other side of the holeto hold the panel in contact with the substrate.

The panel itself includes a decorative layer on the front or exposedside which in some cases may be a woven fabric. Immediately behind thedecorative front layer are two layers of open celled polyurethane foamand sandwiched between the foam layers is a bat of spun fiber glass. Thefiber glass gives the panel tensile strength in all directions anddimensional stability.

The foamed polyurethane is impregnated with a suitable adhesive in anamount sufficient to fill the cells of the foam when the foam iscompressed into the desired shape and thickness during the moldingprocess. Thereby, the foamed resin of both layers will be relativelyhard when the adhesive is cured but flexible enough to provide both gooddimensional stability and easy manipulation into the desired location.

The panel itself is manufactured by assembling the layer between a pairof molds which then compress and heat the laminated structure to curethe adhesive.

For manufacturing efficiency, the mold surfaces are vertically spacedand the lower mold surface includes the outline of a plurality of thedesired shape for the panel. The shape on the lower surface will beoutlined by an upstanding ridge traversing the periphery of the desiredpanel shape. The upper most extent of the ridge is a knife edge designedto cut the panel to shape. The cutting is accomplished after the moldsare pressed together and heated as necessary to cure the adhesive usedin the bonding of the layers. After the upper mold surface has performedits function it is removed and the lower mold surface with the curedpanel thereon is fed through a pair of rollers which will cooperate withthe knife edge of the ridge around the desired panels to cut the panelto the desired shape. Thereafter the excess material outside the ridgeis stripped away and the plurality of panels of the desired shape areextracted for packaging and shipment to an appropriate manufacturer.

Objects of the invention not clear from the above will be understoodfully by a review of the drawings and the description of the preferredembodiment which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a decorative panel according to this invention mounted onthe inside surface of an automobile door;

FIG. 2 is an exploded elevational view showing the molding process andthe layers of the panel in superposed position;

FIG. 3 is a perspective view of the cured panel and lower mold surfacepassing through a pair of rollers to cut the panel to shape;

FIG. 4 is a fragmentary sectional view of the rollers, panel and lowermold surface as the rollers cut the panel to shape; and

FIG. 5 is a fragmentary sectional view similar to FIG. 4 of analternative embodiment to the panel attaching means of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a plastic shell or substrate 10 which serves as theinside surface of a vehicle door and mounted thereon is a panel 12 whichserves as a soft and decorative feature of the door.

The panel 12 itself is a composite of a plurality of layers of materialbonded together by an appropriate adhesive. The visible or exposedsurface is a decorative layer 14 which may be a woven fabric, embossedpolymer or other material.

FIG. 2 illustrates the sequence in which the various layers of thelaminate are assembled. Adjacent to the decorative layer 14 is a foamedpolyurethane layer 16 which is of open celled structure and preferablyabout one-half inch thick. The foam itself has a density of about 1.2lbs/cubic foot and a suitable source of the material is Burkhart Foam,Burkhart, Ind. The preferred foam has an industry deflection designationof 60ILD.

Adjacent the foamed resin layer 16 is a thin layer 18 of spun fiberglass which serves to give dimensional stability and tensile strength tothe panel since the spun fibers are randomly oriented.

The next layer 20 is an open celled polyurethane foam layer havingidentical dimensions and characteristics as layer 16.

The back layer which will be in direct contact with the plastic doorshell 10 is a double sided adhesive tape 22. The preferred tape may beobtained from Avery under the trademark FASTAPE 1125 HX and is anacrylic pressure sensitive adhesive on a polyethylene coated naturalcraft release liner or peel sheet. One side of the pressure sensitiveadhesive is applied directly to the surface of foamed urethane layer 20.The craft paper peel sheet covers the other surface of the pressuresensitive adhesive and will be stripped away at the time the workmandesires to apply the panel 12 to the plastic shell 10.

In the manufacturing process the layers of the panel are stacked oneabove the other on top of a lower mold 24. The structure shown in FIG. 2indicates that the lower mold surface is of two parts and the second 26of the parts includes a plurality of panel shapes bordered by a ridge28.

As best seen in FIG. 4 the shape defined by ridge 28 includes a centralportion of generally planar surface 30 and the ridge 28 extendsgenerally perpendicular to planar surface 30. The upper edge of theridge terminates in a sharp knife edge 32 and its function will beexplained subsequently.

Prior to the assembly of the two polyurethane foamed layers 16 and 20and the fiber glass layer 18, each layer is impregnated with a suitableamount of a particular adhesive which is heat and moisture curable. Theadhesive is applied by conventional apparatus known in the industry andin an amount sufficient to fill the open cells of the foamed urethanewhen the upper section 34 of the press is moved into operative position.Note that the thickness of the foam layers 16 and 20 in FIGS. 4 and 5appear to be different and indeed they may be different. The layerscould be initially one-quarter inch thick or one-half inch thick oranyplace in between depending upon the desired thickness and ultimatestructure of the finished panel. In a panel designed for a door similarto that illustrated in FIG. 1, the ridge 28 will rise less than aboutone-half inch and preferably about one-quarter inch above planar surface30, thereby, when molds 24 and 34 are pressed together there will besubstantial compression of the foamed resin and therefore a great amountof adhesive is not required to fill the voids of the compressedurethane.

The thickness of the foam layers may be greater or smaller than thatspecified for a door panel if circumstances dictate.

The adhesive mixture preferred is about two-thirds polyether polyol,preferably in the range of about 60-75% by volume, to about one-thirdaromatic isocyanate by volume with an appropriate catalyst, although thevolume of isocyanate could range from about 25-40%.

Useful are polyether polyols with the preferred polyol being a hydroxylterminated poly(oxyalkylene) polyol, of appropriate molecular weight,such as obtainable from Mobay Corporation under the trademarks MULTRANOL3900 (mol. wt. about 4800) and MULTRANOL 9157. Such polyether polyolsmay be used singly or in admixture in the adhesive mixture.

The preferred isocyanate is a polymethylenepolyphenylene ester ofisocyanate acid, such as obtainable from Mobay Corporation under thetrade designation MONDUR MR, whose composition consists essentially ofabout 45-55% of diphenylmethane diisocyanate (MDI), about 45-55% ofhigher oligomers of MDI, and a trace of phenyl isocyanate.

Suitable catalysts are available from Air Products and Chemicals, Inc.under the trade designation DABCO T-12 (a specially formulatedhigh-boiling liquid dibutyltin dilaurate) or DABCO 33LV which is atriethylenediamine (TEDA) catalyst and particularly 1,4-diazobicyclo(2.2.2) octane. The proportions of catalyst needed may vary, dependingupon curing temperature, relative humidity of the air and other factorsknown in the industry. By way of preferred example, in the above statedenvironmental conditions, about one and one-half grams oftriethylenediamine are added to each gallon of polyol and followed byabout three-fourth gram of the dibutyltin dilaurate being added to eachgallon of polyol. Preferably the catalysts are added to the polyol priorto its mixture with the isocyanate.

While we have described the preferred embodiment with a particularpolyol, isocyanate and catalyst, it will be clear that the time periodsand the temperatures for curing could be modified by adjustment of thecatalyst and other perimeters and these would be obvious modificationswell within the inventive concept. Similarly, the curing time might bereduced for the liquid resin adhesive by a controlled increase in thehumidity in the vicinity of the furnace.

The age of the foam in the panel should not exceed about thirty days atthe time the panel is formed.

Another feature of the particular mold structure of this invention isbest seen in FIG. 4 and to understand its significance one must be awareof the conventional way of making decorative door panels using the rearmetallic layer to provide the toy tabs. The conventional way to make thepanel is to first make the composite layer. Then apply the decorativefront layer and pull the edges of the decorative layer around to thebackside of the panel where it is held in place by tacks, adhesive,staples or some other mechanism. This invention avoids the need for suchcomplications by a "flush cut" technique. It involves the way the panelshape is severed after the adhesive is cured.

In the initial assembly of the panel layers the decorative layer 14 isfirst deposited. Each piece of the decorative layer is cut somewhat tosize because of the cost of the material. One of the cut decorativefabric layers 14 is applied over each of the ridges 28 and each cutpiece of fabric 14 extends beyond the ridge 28. That is, thepreliminarily cut fabric pattern is larger than the shape defined by theridge 28. It is allowed to rest in place and conform by gravity to theshape defined by the ridge 28, then the adhesive impregnated layers 16,18 and 20 are applied. They are not cut to size because of the cost,they extend substantially the full width and length of the mold 26.Last, the double sided adhesive tape layer 22 is applied, it too extendsfor the full dimensional width and length of mold 26.

Looking now to FIG. 4, it will be observed that fabric layer 14 liessubstantially flat on planar surface 30 except near the edges of thepanel at ridge 28. The decorative layer 14 defines a convex shapecurving back toward the rear surface of the panel. Note also that thereis a space 36 formed between planar surface 30, ridge 28 and decorativelayer 14. Space 36 allows for expansion of the foamed resin andaccommodation by the slightly stretchable fabric layer 14 during themanufacturing process.

To the average consumer the panel of this invention will look the sameas other panels he is used to seeing. That is intentional. The inventionis not in its appearance when installed. The invention is in the panelstructure behind the fabric, the way it is made and the way it isinstalled. Observing again FIG. 4, it will be clear what a casualobserver of the panel 12 will see when he views it from the vantagepoint of FIG. 1. He will see the panel of this invention which appearsto have the fabric extending over and around the peripheral edges of thepanel, the same as prior panels. In fact it does not extend around theedge, it is "flush cut" to give that appearance, it is only molded andcured to shape to give the decorative appearance but without the extrawork.

When mold sections 24 and 34 are pressed together to mold the panels ofthis invention, they are heated to cure the adhesive impregnating thefoamed resin and fiber glass layers. The adhesive is designed to cure atabove 200°F. As a consequence the lower mold surfaces are notintentionally heated above about 150°F. because the mold tends to holdheat during the manufacturing process going from one step to the other,and if it gets above about 150°F. it may tend to cook the adhesiveduring the assembly process. The upper section 34 of the mold will beheated to about 250°F.

The pressure applied to the molds is about 5-50 tons on a mold having across-sectional area of about five feet by four feet having about nineof the panel shapes defined by ridge 28 on the surface. The lineallength of each of the ridges is about sixty-five inches. While theindicated range of pressures is satisfactory the preferred pressureapplied to the mold surfaces is about 35 tons and the time period in theheating furnace at the indicated temperatures is about 21/4 minutes. Thetime period may be increased or decreased depending upon the exacttemperature used, the moisture content of the air which is an inherentingredient in the curing of the adhesive, and the catalyst used.

After the appropriate temperature is achieved and curing times have beencompleted, the mold is removed from the furnace and the upper moldretracted to an out of the way position. In this instance, the moldsection 26 and the cured composite are moved to a cooling section andthen fed through a pair of pinch rollers 38, 40 which will serve to cutthe overlap of the panels at the knife edge 32 of ridge 28. The scrapmaterial may then be stripped and discarded and the formed panels may becollected as ready for assembly or shipment to an appropriate assemblyfacility.

FIG. 5 shows another embodiment for attaching the panel 12 to thesubstrate 10. It includes a CHRISTMAS TREE structure 42 comprising aresin stud having a head 44 on one end of a shaft 46 and along the shaftare a plurality of radially extending flanges 48. The CHRISTMAS TREE isdesigned to project through a hole in substrate 10 where the hole has asmaller cross-sectional area than the flanges 48. The flanges aredesigned to deflect toward the head 44 as they pass through the holeunder pressure applied against the head 44 from the fabric side of thepanel. After the flanges pass through the hole they will deflectradially and then will hold the panel tightly against the substrate. Thehead 44 is located between the fiber glass layer 18 and first foamedlayer 16; the fiber glass helps prevent the stud from being pulled fromthe panel.

It will be understood that in the manufacturing process using theCHRISTMAS TREE illustrated in FIG. 5 suitable holes would be required inthe bottom surface of mold section 34 to accommodate the studs 42.Similarly annular grooves in roller 38 would be required for the samereason.

Having thus described the invention in its preferred embodiment, it willbe clear that other modifications may be made without departing from thespirit of the invention. Also the language used to describe theinventive concept and the drawings accompanying the application toillustrate the same are not intended to be limiting on the inventionrather it is intended that the invention be limited only by the scope ofthe appended claims.

We claim:
 1. A composite panel comprising, a series of layers bondedtogether having two faces and an edge periphery,one face comprising alayer of decorative material, said one face being substantially planarexcept adjacent said periphery, adjacent said periphery said decorativematerial curving toward a second face to define a convex surfaceterminating at said periphery, said decorative material being bonded toone side of a first foamed resin layer by an adhesive impregnating saidfoam, said foam being open celled and the adhesive being cured to fillthe open cells, the other side of said first foamed resin layer beingbonded to a fiber glass layer, said fiber glass layer being bonded to asecond open celled foamed layer, means adhered to said composite panelfor connecting the panel to a substrate and the periphery of said panelbeing compressed to a minimal thickness with the decorative materialterminating substantially at said second face.
 2. The panel of claim 1wherein the second foamed resin layer is impregnated with adhesive tofill the open cells, said adhesive impregnating both said foamed layersbeing a mixture of about 60-75% polyol, 25-40% isocyanate and acatalyst.
 3. The panel of claim 2 wherein the means adhered to saidcomposite panel for connecting the panel to a substrate comprises atleast one flanged resin stud having a shaft with a head on one end, saidhead being located between said first foam layer and said fiber glasslayer, the shaft of the stud bearing the flanges extending through thefiber glass layer and the second foamed layer and beyond for a distancegreat enough to allow the shaft and flanges to project through a hole insaid substrate, said hole having a cross-section smaller than saidflanges passing therethrough, said flanges being flexible to the extentthat they will (1) deform to pass through the hole upon sufficientpressure being applied in the area of the head and (2) spring back intoposition to hold the second face of the panel against the substrate. 4.The panel of claim 2 wherein the means adhered to said composite panelfor connecting the panel to a substrate comprises a pressure sensitivedouble sided adhesive tape, one side of said adhesive tape being bondedto one side of said second foamed layer, the other side of said adhesivetape being covered with a peel strip.
 5. The panel of claim 1 whereinthe means adhered to said composite panel for connecting the panel to asubstrate comprises a pressure sensitive double sided adhesive tape, oneside of said adhesive tape being bonded to one side of said secondfoamed layer, the other side of said adhesive tape being covered with apeel strip.
 6. The panel of claim 1 wherein the means adhered to saidcomposite panel for connecting the panel to a substrate comprises atleast one flanged resin stud having a shaft with a head on one end, saidhead being located between said first foam layer and said fiber glasslayer, the shaft of the stud bearing the flanges extending through thefiber glass layer and the second foamed layer and beyond for a distancegreat enough to allow the shaft and flanges to project through a hole insaid substrate, said hole having a cross-section smaller than saidflanges passing therethrough, said flanges being flexible to the extentthat they will (1) deform to pass through the hole upon sufficientpressure being applied in the area of the head and (2) spring back intoposition to hold the second face of the panel against the substrate. 7.A process for forming a panel comprising,providing a mold having upperand lower sections, the upper section having a first planar surfacefacing the lower section, the lower section including a second planarsection, providing a border ridge around the second planar section, saidridge projecting toward said upper mold section and including a sharpcutting edge at its upper most edge which extends around the secondplanar surface, the height of said ridge being less than about one-halfinch above the second planar section, providing a decorative layer toprovide one face for said panel, cutting the decorative layer to aboutthe shape defined by said sharp edge, placing the decorative layer onthe lower mold in a position that the decorative layer covers the sharpedge and extends beyond said sharp edge at all locations, providing afirst layer of open celled foamed resin of a thickness in the range ofabout 1/4-1/2 inches, impregnating the foamed layer with an adhesive inan amount which will fill the cells upon compression to the desiredthickness of the cured panel, placing the first layer of foam over thedecorative layer in a manner to completely cover the decorative layer,placing a layer of fiber glass of a size at least as the decorativelayer over said first foamed layer, placing a second foamed layeridentical to said first foamed layer over said fiber glass layer,pressing the two mold sections together to compress the layers betweenthe planar sections and at the sharp ridge edge, heating the lower moldsection to about 150°F. and the upper mold section to about 250°F. for aperiod of time adequate to cure the adhesive.
 8. The process of claim 7further including, after the adhesive is cured, removing the upper moldsection and running the lower mold section and cured panel between apair of compression rollers to cut the panel at the sharp ridge edge. 9.The process of claim 8 including, before pressing the two mold sectionstogether, applying means to said panel for connecting the panel to asubstrate.
 10. The process of claim 9 wherein the connecting meanscomprises at least one flanged resin stud having a shaft with a head onone end, said head being located between said first foam layer and saidfiber glass layer, the shaft of the stud bearing the flanges extendingthrough the fiber glass layer and the second foamed layer and beyond fora distance great enough to allow the shaft and flanges to projectthrough a hole in said substrate, said hole having a cross-sectionsmaller than said flanges passing therethrough, said flanges beingflexible to the extent that they will (1) deform to pass through thehole upon sufficient pressure being applied in the area of the head and(2) spring back into position to hold the second face of the panelagainst the substrate.
 11. The process of claim 9 wherein the connectingmeans comprises a layer of double sided pressure sensitive adhesivetape, placing a layer of said adhesive tape over the second layer offoam, one side of said tape adhesively bondable to said second layer offoamed resin, the other side of said adhesive tape facing the planarsurface of the upper mold section being covered with a peel strip, theadhesive tape being of a size to cover the second layer of foamed resin.12. The process of claim 7 including, before pressing the two moldsections together, applying means to said panel for connecting the panelto a substrate.
 13. The process of claim 12 wherein the connecting meanscomprises at least one flanged resin stud having a shaft with a head onone end, said head being located between said first foam layer and saidfiber glass layer, the shaft of the stud bearing the flanges extendingthrough the fiber glass layer and the second foamed layer and beyond fora distance great enough to allow the shaft and flanges to projectthrough a hole in said substrate, said hole having a cross-sectionsmaller than said flanges passing therethrough, said flanges beingflexible to the extent that they will (1) deform to pass through thehole upon sufficient pressure being applied in the area of the head and(2) spring back into position to hold the second face of the panelagainst the substrate.
 14. The process of claim 12 wherein theconnecting means comprises a layer of double sided pressure sensitiveadhesive tape, placing a layer of said adhesive tape over the secondlayer of foam, one side of said tape adhesively bondable to said secondlayer of foamed resin, the other side of said adhesive tape facing theplanar surface of the upper mold section being covered with a peelstrip, the adhesive tape being of a size to cover the second layer offoamed resin.
 15. The process of claim 7 including, during assembly ofthe decorative layer on the lower mold, depositing the decorative layerin a manner to allow it to conform to the lower mold surface and ridgeby gravity to thereby provide, adjacent to and inside the ridge, anexpansion zone for the panel when it is compressed by the upper moldsection, the resulting decorative layer surface approaching the ridgesbeing a convex curve.
 16. The process of claim 8 including, duringassembly of the decorative layer on the lower mold, depositing thedecorative layer in a manner to allow it to conform to the lower moldsurface and ridge by gravity to thereby provide, adjacent to and insidethe ridge, an expansion zone for the panel when it is compressed by theupper mold section, the resulting decorative layer surface approachingthe ridges being a convex curve.
 17. The process of claim 9 including,during assembly of the decorative layer on the lower mold, depositingthe decorative layer in a manner to allow it to conform to the lowermold surface and ridge by gravity to thereby provide, adjacent to andinside the ridge, an expansion zone for the panel when it is compressedby the upper mold section, the resulting decorative layer surfaceapproaching the ridges being a convex curve.
 18. The process of claim 10including, during assembly of the decorative layer on the lower mold,depositing the decorative layer in a manner to allow it to conform tothe lower mold surface and ridge by gravity to thereby provide, adjacentto and inside the ridge, an expansion zone for the panel when it iscompressed by the upper mold section, the resulting decorative layersurface approaching the ridges being a convex curve.
 19. The process ofclaim 11 including, during assembly of the decorative layer on the lowermold, depositing the decorative layer in a manner to allow it to conformto the lower mold surface and ridge by gravity to thereby provide,adjacent to and inside the ridge, an expansion zone for the panel whenit is compressed by the upper mold section, the resulting decorativelayer surface approaching the ridges being a convex curve.
 20. Theprocess of claim 12 including, during assembly of the decorative layeron the lower mold, depositing the decorative layer in a manner to allowit to conform to the lower mold surface and ridge by gravity to therebyprovide, adjacent to and inside the ridge, an expansion zone for thepanel when it is compressed by the upper mold section, the resultingdecorative layer surface approaching the ridges being a convex curve.